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Warning: pic heavy, as usual.
Welcome to my first review of lights featuring the new XP-G Gen2 (aka XP-G2) emitter.

According to Cree, these XP-G2 emitters are supposed to have "up to 20% higher lumen output" over XP-G (more on that later ...). Foursevens has started swapping in XP-G2 to their existing XP-G line up. Note that with the recent name change from 4Sevens to Foursevens, the model numbers for all their lights have changed as well. In this case, I have the Foursevens QTLC (1xCR123A/RCR, formerly the Quark Tactical 123) and the QB2A (2xAA/NiMH, formerly the Quark Turbo AA-2).

Let's see how they do

Manufacturer Reported Specifications: (note: as always, these are simply what the manufacturer provides  scroll down to see my actual testing results).

Interesting tid-bit here: Foursevens' specs do not appear to be updated for the XP-G2 (i.e., these specs are unchanged from the original XP-G models under the Foursevens label).

Packaging for the Foursevens brand has also been updated from the earlier 4Sevens models. The lights now come in a thin gray cardboard box, similar to the original black-box Quark models (although the cardboard is much thinner and more easily damaged now).

Inside the presentation-style box, you will find a clamshell plastic case with the light and all bundled extras. Both lights came with batteries (Foursevens-branded CR123A, or Duracell alkaline AA), good quality lanyard, split ring for keychain attachment, spare o-rings, decent quality holster with velcro closing flap, and appropriate size rubber hand-grip.

I will focus here on the general build and common interface of the two lights, and then delve into the detailed testing results for each model.

QTLC

QB2A

Both lights have a glossy black finish (hard anodized), with no obvious chips or damage on my samples. Both lights have a generous amount of knurling to help with grip, and the knurling is of reasonable aggressiveness. Lettering is bright white and sharp against the black background.

The QTLC looks a lot like the original Quark 123, but without the pocket clip. The QB2A has a removable pocket clip secured in place by its own cover/grip ring (i.e. unscrew the ring to remove the clip, screw back down to cover the gap where the clip attaches).

The QTLC has holes on the side of the tailcap for a split-ring or lanyard attachment. The larger QB2A tailcap has a cut-out region of reasonable thickness. Both lights feature a protruding forward clicky switch (Foursevens "Tactical" interface, as explained below).

Both lights use square-cut screw threads (or more accurately, trapezoidal), at both ends of the battery tubes. Threads are not anodized on the body, but the tailcaps have anodization to provide tail lock-out. This arrangement is less secure for lock-out than dual anodizing, but it does allow you to reverse the direction of the body tube (useful for models with a clip, like the QB2A).

Emitters/Reflectors:

QTLC

QB2A

The QTLC has a medium orange peel (i.e., textured) reflector. The QB2A has larger head with smooth deep reflector for maximum throw. Both lights had well-centered reflectors on my samples. Visually, the XP-G2 doesn't look very different from a typical XP-G  except for a silver circuit board mask instead of green. I doubt the reflectors have changed any from the earlier XP-G models.

Note that the Cree specsheets report a lower emission angle for the XP-G2, down to 115 degrees (from 125 degrees on the XP-G). So there are likely to be some small beam pattern differences when used with the same reflector design.

Scroll down for specific beamshots of each model, relative to its class counterparts.

With the Tactical interface, you can configure the bezel loose/tight states to have one memorized level from the total mode set (i.e, head tight for one set mode, head loose for another). Available modes to select from when programming the states are Moonlight, Lo, Med, Hi, Turbo, SOS, Strobe, and Beacon mode, in sequence.

To reprogram the each bezel state, you need to loosen-tighten the head 4 times quickly, ending in the state you want to re-program. After 3 secs, the light will flash 3 times, and you can now advance through all the possible modes by soft-pressing or clicking off-on at the tailswitch. To select the mode you want memorized, wait 10 secs with the light on in that mode. The light will flash rapidly, signifying memorization of the mode state. It is now safe to turn off - it won't change unless you go through the programming mode again.

As always, please see my detailed examination of the build and user interface in my video overview:

Video was recorded in 720p, but YouTube typically defaults to 360p. Once the video is running, you can click on the configuration settings icon and select the higher 480p to 720p options. You can also run full-screen.

PWM/Strobe

There is no sign of PWM that I can see, at any output level  the lights appear to be current-controlled, as always.

All my output numbers are relative for my home-made light box setup, a la Quickbeam's flashlightreviews.com method. You can directly compare all my relative output values from different reviews - i.e. an output value of "10" in one graph is the same as "10" in another. All runtimes are done under a cooling fan, except for any extended run Lo/Min modes (i.e. >12 hours) which are done without cooling.

All lights are on Turbo/Max on 1x AW protected RCR in the first set of panels, followed by 1xCR123A in the second. Lights are about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences.

And now on primary 3V 1xCR123A:

Again, a fairly typical beam for this size light. Beam pattern doesn't seem very different from a standard XP-G-equipped light.

Foursevens has done a good job keeping output consistent across primary CR123A and rechargeable Li-ion battery sources. However, as always, my estimated ANSI FL-1 lumens are higher than the Foursevens specs. But all my lights are tested in a consistent way, so the relative relationships in the tables still hold.

Output/Runtime Comparison:

The QTLC is a good performer for the class and output level, but the XP-G2 doesn't appear to offer any obvious advantage over competing XP-G R5/S2 equipped lights. More on this in my comments at the end.

All lights are on Max output on 2x Sanyo Eneloop AA NiMH. Lights are about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences.

Note: I have included a recent XP-G-equipped QB2A in the comparisons below. It is specifically labelled "QB2A XP-G". The new XP-G2-equipped QB2A is labelled "QB2A XP-G2".

The XP-G2 version of the QB2A appears to throw a slightly tighter hotspot (i.e., more narrowly focused). Hard to tell from a single sample of each, though. In any case, the QB2A is one of the best throwing 2xAA lights I've tested to date.

UPDATE November 4, 2012: I've updated my summary table below with the results of an earlier stock Foursevens Quark AA-2 Turbo XP-G (identical to the QB2A XP-G model previously compared to here). See discussion at the end of the review.

Again, my estimated ANSI FL-1 lumens are higher than the Foursevens specs. But all my lights are tested in a consistent way, so the relative relationships in the table still hold.

Output/Runtime Comparison:

The first thing you are likely to notice above is that the XP-G2 version of the QB2A is not that much brighter or longer-lasting than the preceding XP-G version of the QB2A.

On Hi or Turbo, the XP-G2 version of the QB2A is only ~4-6% brighter than the QB2A XP-G version, across most of the runs. Overall runtime is pretty much the same as well, with only a ~1-3% gain for the XP-G2 version on the modes tested (which is well within normal variation for a given model/emitter). I will discuss this limited output increase further in my comments at the end of the review.

---------

Potential Issues

Both my review samples show evidence the common "pre-flash" issue (i.e., when reset to a low output mode, the lights will sometimes come on with a brief high-intensity burst). This seems to occur mainly when you switch down to a lower output mode shortly after turning the light off in a higher mode. It is believed to be due some residual power remaining in the circuit for a short period of time after turning off (and has been around since the early days of the early Fenix, Olight and Foursevens models).

The tailcaps feature screw thread anodizing, so a physical lock-out is possible. However, this may not be as robust as lights where both the body and tailcap threads are anodized (i.e. a scratch to the tailcap threads may invalidate the lock-out). The body tubes are reversible in on these lights (i.e., identical threading), so you can reverse the pocket clip (when present) by switching the orientation.

Overall output with the new XP-G2 emitters does not appear to have increased much over typical XP-G emitters (see discussion below). But as usual with Foursevens, my estimated ANSI FL-1 lumens are higher than the reported output specs.

There was apparently some concern over available tint bins with the early XP-G2s. I haven't noticed anything unusual about my two samples. I would describe them as at the cooler end of cool white - but still within what I consider a normal acceptable range.

Preliminary Observations

XP-G2 vs XP-G

Before discussing the relative merits of the Foursevens lights, I thought I would explain the differences between these two classes of emitters  especially in terms of my output findings. I'm afraid the Cree marketing on the XP-G2 may be a bit misleading/confusing. "Increasing lumen output up to 20%" (relative to XP-G) is a phrase you are seeing lot of in their promotional material  it's even in the product data sheet.

But to be more technical, what has actually happened is that the XP-G2 delivers up to 20% more lumens per Watt than the classic XP-G of comparable output bin (see the Cree main XP-G2 product page). Lumens/W is the traditional measure of luminous efficacy, which is not the same thing as actual output (i.e., lumens, aka luminous flux). As an aside, they appear to have increased efficacy mainly by lowering the forward voltage (Vf) with the new die design.

What this means is that there is now more "headroom" on the new XP-G2 platform, and higher output XP-G2 emitters can ultimately be produced. Unfortunately, directly comparing back to XP-G is complicated by the more stringent testing and reporting measures Cree is now using for XP-G2 binning. XP-G emitters were previously output bin rated by luminus flux @350mA, @25 degree C. With the XP-G2, Cree has switched to a more representational (but more stringent) @85 degree C for binning purposes. This means that the XP-G2 output bins are actually brighter than the XP-G output bins with the same bin number.

As a result, you have to be careful when looking up the spec tables to ensure you are comparing under the same conditions. If you do (i.e., compare both classes under the same 25 degrees C conditions), you will see that the new XP-G2 bins are exactly two bin steps brighter than the same bin number on XP-G. So a XP-G2 R3 is the same output bin as a XP-G R5, for example.

This will be confusing to many, as it now means that a typical XP-G2 R5 is  on average - ~13% brighter than a XP-G R5 (and so on, for the R3 and R4 bins). Of course, given the range within a bin, this also means that for any given specific XP-G2 sample could be anywhere from ~7-20% brighter than a comparably bin-numbered XP-G sample. This may be how they got that "up to 20% brighter" phrase. You really have to think of these things statistically  the bins are a range, and you don't know where exactly in the range any given sample will fall.

And it doesn't stop there. What happens if you compare to the new XP-G2 R5 bin to XP-G S2 bin? In that case, you are only one bin step up now, which means a given XP-G2 R5 could be anywhere from ~1-14% brighter than a given XP-G S2 (on average, ~6-7% brighter). Note that the numbers above are based on the 350mA @25 degree C binning process specifically, but the general relationships should hold reasonably consistent across most drive levels in a regular flashlight.

Now, Foursevens (like most manufacturers) doesn't generally provide information on specific output bins in their lights (except for some limited edition runs). You will notice in my testing here that my XP-G2-equipped QB2A is only ~5% brighter than my XP-G-equipped QB2A. This suggests to me that my XP-G2 review light is likely only one bin step up from the earlier XP-G model. This may very well be why Foursevens didn't change the minimum specs for their lines when they went to XP-G2.

UPDATE November 4, 2012: Given the single bin step difference on my QB2A samples, I strongly suspected my QB2A XP-G was a S2 output bin (but have no way to verify). I just picked up am old-stock model Foursevens Quark AA-2 Turbo (identical to the QB2A - it just has the earlier 4Sevens logo and model numbering). As you will see in the summary table, my QB2A XP-G was ~10% brighter overall than my Quark AA-2 Turbo XP-G. This would be consistent with a R5 output bin for the Quark AA-2 Turbo sample, and a S2 output bin for the QB2A, for example.

There is one other significant change between XP-G2 and XP-G  the emitter angle has dropped to 115 degrees from 125 degrees. As a result, you can expect to see some consistent beam differences when paired with the same secondary optic (i.e., when using the same reflector as a XP-G light). In my limited direct experience of the two QB2A lights, it seems like the XP-G2 equipped version has a smaller and more tightly-defined hotspot. This translates into increased throw in my testing (i.e., peak output was only ~4% higher on my QB2A XP-G2 sample, but lux @1m was ~16% higher than the XP-G version).

QB2A and QTLC lights

Although more evolutionary than revolutionary, I like the new updates to the venerable Quark line. Physically, the lights have gone through a number of revisions since their initial launch, and the feel and use is very good.

The lights also continue to come with a good number of extras  definitely a nice overall package. While I would like to see double-anodizing for the tail-threads, there is not much else to fault in the design  they are solid lights for their respective classes.

Note that this is my first review of a "Turbo" model from Foursevens, and I am impressed by how much throw you get for a 2xAA light. The QB2A in particular feels comfortably "beefy" in the hand, with good grip and handling. Probably one of the better "throwy" options to consider in this class, if you don't want to step up to the larger 4xAA lights.

As explained above, the current XP-G2 upgrade added only a fairly nominal bump in output in my testing (with a more significant increase in throw). That might make the older XP-G versions a good buy, if you can still find any on close-out. Note however that my recent purchase of an old stock Quark AA-2 Turbo (earlier logo/labeling of the QB2A, but otherwise identical) was a clear two bin steps down for the new QB2A XP-G2 sample I reviewed here.

All in all, the XP-G2 is a better longer-term platform, and we will hopefully continue to see higher output bins coming. Definitely a nice update for those looking for more "throwy" options.

This ANSI thing needs to stop, or they need to expand the window [at least double] when testing is done to determine maximum output. That way the rejected heat from the LED can't be greater than the body's dissipation ability.
That was very misleading of Cree & 4Sevens to say 20% more lumens, when they meant LPW.
So the only good things about this evolution of the Si3 'platform': slightly lower Vf, and reduced apparent size from larger dome. (and incremental improvements on light extraction, phosphor improvements)
oh and the xp-e2 should silence all those who keep nagging for the return of the xr-e. It is 2013, let it go.

I'm suprised how well tiny Nitecore EA2 with "old" emitter keeps up with QB2A in terms of throw and overall brightness/runtime.

Yes, the Explorer series are remarkably good throwers for the size. Of course, the only way it matches the throw of the XP-G-version of the QB2A is by being driven ~20% brighter initially (i.e., before step down occurs).

Originally Posted by MichaelW

So the only good things about this evolution of the Si3 'platform': slightly lower Vf, and reduced apparent size from larger dome. (and incremental improvements on light extraction, phosphor improvements)

Yes, it seems like the main benefit of XP-G2 is that it provides more "headroom" to produce higher outputs bins. In terms of XP-G, except for the occasional "premium" S2 batch, they seem to have been largely tapped out around R5 for quite some time now. But based on the Cree specs, the current XP-G2 R5 is really just the next bin up from the XP-G S2.

Yes, the Explorer series are remarkably good throwers for the size. Of course, the only way it matches the throw of the XP-G-version of the QB2A is by being driven ~20% brighter initially (i.e., before step down occurs).

But it's not much diommer after stepdown, with still very impressive runtime. I think that with XP-G2 EA2 would smash QB2A in basically every category. Unfortunately Nitecore isn't very keen to replace emitters in their flashlights.

But it's not much diommer after stepdown, with still very impressive runtime. I think that with XP-G2 EA2 would smash QB2A in basically every category. Unfortunately Nitecore isn't very keen to replace emitters in their flashlights.

It's true the EA2 is a good throw platform. But that light steps down >25% from its peak ANSI FL-1 output (reported here), so I would expect throw to be similarly reduced by a comparable amount.

Ahh, thanks. Finally understood the bin steps. It gets confusing when you take into account the new XP-E R4 or XP-E HEW which seemed like it was just following on from the old XP-E R3. I don't really understand why Cree are marketing the G2 this way. The 20% figure is very misleading.

I don't really understand why Cree are marketing the G2 this way. The 20% figure is very misleading.

Well, I can understand why they have switched to the more stringent bining process (i.e., 350mA @85 degrees C is more representational of the real world than 25 degrees C was). But I agree that "up to 20%" figure is not very helpful.

Originally Posted by SuLyMaN

Sorry if I keep repeating myself over and over, but your reviews are truly phenomenal and you do answer questions which is awesome

Thanks, glad to hear folks are finding them useful.

As an aside, this is the first time I've reviewed a Quark "Turbo" model (i.e., the QB2A, which directly replaces the old Quark AA-2 Turbo). It definitely seems to be an excellent choice for those looking for max throw in the 2xAA format.

I've updated this review with the results of an earlier stock Foursevens Quark AA-2 Turbo XP-G that I just picked up. Note that this light is identical to the QB2A XP-G model previously compared to here (i.e., it is just the older logo/labeling).

Given the single bin step difference between my QB2A samples, I strongly suspected my QB2A XP-G was a S2 output bin (but have no way to verify). As you can see in the summary table, my QB2A XP-G was ~10% brighter overall than my Quark AA-2 Turbo XP-G. This would be consistent with a R5 output bin for the Quark AA-2 Turbo sample, and a S2 output bin for the QB2A, for example.

It thus seems reasonable that you could expect one or two bin steps up with the QB2A XP-G compared to the earlier QB2A/Quark AA-2 Turbo XP-G models.

Thank You selfbuilt for the great explanation of XP-G vs. XP-G2, especially with regard to how the bins relate to each other.

My only experience so far with XP-G2 is a nailbender P60 dropin. I was very surprised with how well it throws for a standard P60 reflector, but to my eyes the hotspot was also larger than a typical XP-G P60. The XP-G2 hotspot was fatter than an XP-G, but still narrower than the XM-L. I'll give you that this is completely non scientific, but that is my first impression. I'll have to pay more attention to what you and others see because from what you have described here my dropin example is not exactly what I would expect to see.

Would the QB2A and Eneloops be a good recommendation for a friend that needs a light to check their dogs out behind their house out to 100 yards. My G5 does a good job at 100 yards, but wouldn't the Eneloops be safer for a non enthusiast than the 18650.

Would the QB2A and Eneloops be a good recommendation for a friend that needs a light to check their dogs out behind their house out to 100 yards. My G5 does a good job at 100 yards, but wouldn't the Eneloops be safer for a non enthusiast than the 18650.

The G5 is higher output and throwier than the QB2A, but I would think the QB2A would be a fine choice for a non-flashaholic at that distance. As you say, NiMH is a safer for the general user.

I'm not entirely sure how useful comparisons of xp-g2 lights against xp-g lights are considering that the output is entirely dependent on how much current the manufacturer is driving through the emitter, which is all over the board with the various lights out there. I would be interested in a comparison of the current draw of each from models producing roughly equivalent output, though

anyone tested utput and runtime of the turbo aa using a single aa body?

Not a lot of info with the new emitters, but it should be fairly representative. The regular head should have basically the same driver as the Turbo, so I'd use that as a proxy, but there's a 1x14500 test on post 70.http://www.cpfmarketplace.com/mp/sho...testing!/page3